1. Field of the Invention
The present invention relates to display devices and methods for driving display devices, and particularly to a display device capable of displaying three-dimensional (3D) images and a method for driving the display device.
2. Description of the Related Art
Display devices are widely used, ranging from large display devices such as television devices to small display devices such as mobile phones. High value-added products will be needed and are being developed. In recent years, display devices that can display 3D images have been developed in order to display more realistic images.
As methods for displaying 3D images, there are a method using glasses for separating an image seen with a left eye and an image seen with a right eye (also referred to as stereoscopy or image separation method), and autostereoscopy (a naked eye method) by which 3D images can be seen by the naked eye by addition of a structure for separating an image seen with a left eye and an image seen with a right eye in a display portion. It is not necessary to prepare glasses to see autostereoscopic 3D images, which offers a high convenience. Autostereoscopic 3D display is coming into widespread use such as mobile phones and mobile game consoles.
As a method for displaying autostereoscopic 3D images, there is known a parallax barrier method in which a parallax barrier is added to a display portion. A parallax barrier for this method is a stripe-shaped light-blocking portion and causes a decrease in resolution when display is switched from 3D display to two-dimensional (2D) display. In view of this, for a parallax barrier method, there is suggested a structure in which a liquid crystal panel having a patterned transparent electrode is used, and when display is switched between 2D display and 3D display, transmission or blocking of light by a liquid crystal layer is controlled by controlling voltage applied to the transparent electrode in order to set the presence or absence of a parallax barrier (see Patent Document 1).